1. Field of the Invention
This invention relates to a secure system comprise of a plurality of remote terminals and at least one central station for receiving data monitored and reported by each of the remote terminals. In particular, this invention relates in one illustrative embodiment thereof to a system of remote terminals, which monitors and accumulates data relating to pay per view television programs that have been authorized at the remote terminal and, thereafter, reports such program data in a secure fashion as will prevent potential interference or interception by a viewer at the remote terminal.
2. Description Of The Prior Art
There are many applications for monitoring and reporting systems from a plurality of remote terminals. In the absence of such systems, the accumulation of data or the periodic monitoring of conditions at a large number of diversely located remote terminals would be a time consuming and expensive job if accomplished by readers traveling to each location. It is thus desirable to accumulate such data at a central location without the necessity of traveling to each terminal and with a minimum of human intervention. Typically, such systems have been employed to monitor utility consumption, e.g. water, gas, and/or electricity, in private homes or commercial establishments. At each such remote location, a terminal is disposed with sensors or monitors particularly adapted for monitoring an activity at that remote location, storing the monitored data and subsequently reporting the accumulated data on a periodic basis to a centrally disposed station. A host computer is typically disposed at the central station for receiving reports from each of the remote terminals and for using the reported data to bill the customer for the rendered services or consumption.
In an illustrative embodiment of this invention, this secure system relates to a pay per view television (TV) system which monitors each TV program that a viewer at the remote terminal authorizes and, thereafter, reports to the host computer data indicative of the authorized programs and a code identifying the remote terminal and viewer. In addition, it may be desirable to report the actual viewing time, as well as to identify the particular viewed program or a channel on which a particular pay per view program was transmitted.
As described in "PAY-PER-VIEW: THE LOGISTICS, Alternative Pay-Per-View Technologies: A Load Capacity Analysis," by Shellie Rosser, CABLE MARKETING, June 1986, there are two types of pay per view systems: real time and non-real time systems. Real time systems require that a prospective viewer must first place an order with the central station to authorize the selected program. Such a preorder may be placed over a conventional, non-dedicated telephone line or a dedicated cable interconnecting the remote terminal and the central station. The central station responds to the preorder and forwards an enabling message addressed the particular remote terminal from which the selected program was ordered.
An inherent limitation in such real time systems lies in the capacity of the central station to receive and process program preorders in that interval of time immediately proceeding the program transmission time. In real time systems where telephone lines are employed, human operators can handle typically one order per minute, thus significantly limiting those "impulse buyers" who decide at the last minute to view a particular, pay per view TV program. To in part overcome the limitations of a human operator, some real time systems employ automated voice-response apparatus at the central station, which recognizes the tones transmitted from a conventional dual tone modulated frequency (DTMF) tone dialing phone. However, human operators must still handle orders received from viewers without DTMF tone dialing phones.
Even with such automated equipment, the host computer at the central station must perform a credit check and, if good, download the viewer s telephone and account numbers to an addressable controller, which in turn transmits the enabling message to the ordering remote terminal. Such real time systems may be further streamlined by employing an auto-dialer at the remote terminal, whereby the order is automatically transmitted to the central station. Alternative to the use of conventional telephone transmission lines is the use of two-way cable systems, which are capable of transmitting TV program orders at an exceptionally high speed from the remote terminal to the central station. The improved capability of these real time systems is achieved at greater and greater expense as automated apparatus is employed at the remote terminals and at the central station, or as a two-way cable system is employed instead of a conventional telephone transmission line.
In a non-real time system, it is not necessary to transmit first a preorder to a central station. Rather, the viewer actuates a remote terminal, whereby a decoding or descraming apparatus at the remote terminal authorizes or permits access to the selected pay per view TV program as transmitted to the r&lt;mote terminal on a cable. Thus, the viewer may authorize a selected TV program and have it immediately descrambled and available for viewing without delaying to communicate with the central station. Once selected and authorized, data identifying the selected pay per view TV program is stored in the terminal's memory. At a later time, the remote terminal transmits a report message to the central station by a second cable, or by a conventional telephone transmission line.
Examples of non-real time pay per view TV systems are provided by U.S. Pat. No. 4,361,851 of Asip et al. and U.S. Pat. No. 4,104,486 of Martin et al. The Asip et al. system is implemented by a microprocessor, and a memory for storing the time of day and channel identification of an authorized pay per view TV program. The Asip et al. system also includes a telephone interface for determining if the viewer's telephone is in use or free. At selected times controlled by a real-time clock, the remote terminal of Asip et al. initiates a call to a central station to report periodically the programs authorized by the viewer. If the subscriber's phone is busy, the remote terminal will initiate a call at a later time when the viewer's telephone is free. Each remote terminal and its viewer have a unique identity code, whereby the viewer may be billed. The host computer at the central station may transmit control messages to the remote terminal, e.g., transmit a message to deactuate the remote terminal if the viewer has not paid his/her bill. The Asip et al. system also includes a 24 hour real time clock that is used to transmit at predetermined intervals a report message including data indicative of the authorized program(s) and the identity code of the remote terminal to the central station. In addition, Asip et al. provides the viewer with a limited time, e.g., one minute, to preview the authorized program before charging the viewer. In particular, Asip et al. employs a transient or buffer memory for storing program authorization data and a timer in the form of a software timing loop that upon timing out causes the transfer of the program authorization data from the buffer memory, if still there, to a second memory, from which it may be transmitted to the central station.
The Martin et al. patent '486 also relates to a remote terminal for monitoring and accumulating data pertaining to the pay per view TV programs accessed at a remote terminal identified by a unique code. The remote terminal transmits a message reporting program data to a central station over non-dedicated telephone lines. A host computer at the central station receives these report messages and generates bills in accordance with the authorized programs. At each remote terminal of Martin et al., there is included a telephone dialing apparatus that upon command of a preconditioning circuit seizes a telephone line and transmits the report message. The preconditioning circuit includes one or more timers, each of which generates an output pulse at predetermined timed periodic bases, e.g., every two weeks or once a month. The output pulses serve to precondition the telephone dialing apparatus to in turn report the accumulated pay per view program data.
The advantage of a non-real time system is its ability to accommodate the impulse viewer, who at a time immediately prior to or at the beginning of a pay per view TV program wishes to authorize the viewing of that program. In contrast to real time systems wherein it is necessary to transmit a preorder to a central station to authorize the selected program, a non-real time program simply records the authorized program and reports that program and the unique code of the remote terminal at a later time to the central terminal for billing purposes. A significant problem associated with non-real time systems relates to attempts to defeat the reporting of authorized pay per view TV programs at a later time by tampering with the remote terminal. Typical of such attempts is the removal of power from the remote terminal as by unplugging the power line in the hopes that the remote terminal will be able to neither store data indicative of the authorized pay per view TV program, nor at a subsequent time to transmit a message reporting the accumulated pay per view program data to the central station.
Efforts to secure a remote terminal from attempts to prevent accurate reporting, are further complicated by the desire to provide the viewer with a preview of a particular pay per view TV program, before the viewer is charged for that program. Typically, the viewer will select that channel on which a pay per view TV program will or is currently appearing. The viewer will actuate his/her remote terminal to authorize and to descramble the program signal so that it will be displayed as an unscrambled image upon the viewer's TV set. It is desired to provide a grace or preview period of a relatively short interval in which the viewer may decide whether he/she wants to watch that program. If not, the viewer will deactuate the remote terminal, otherwise if the viewer continues to watch the program, the pay per vie TV program will be recorded and, subsequently, a report message will be forwarded to the central station reporting the authorizing and viewing of that pay per view TV program.
The Martin et al. patent '486, described above, implemented such a preview by using a temporary or buffer memory for storing a signal indicative of a pay per view TV program and if present in the buffer memory after a predetermined interval, that signal was loaded to a memory from which it would be transmitted as a return message to the central station. A viewer could use the knowledge of the length of such a preview interval to defeat the reporting of the TV program, by repeatedly authorizing and deauthorizing a particular pay per view TV program within the preview interval throughout the entire length of the program without having triggered the downloading of the pay per view TV program signal from the buffer memory of Martin et al. and, therefore, to avoid the reporting and billing for the viewed pay per view TV program.
A further scheme to defeat reporting of a viewed pay per view TV program, involves the authorization on the remote terminal of a pay per view TV program and, thereafter, removing power from the remote terminal before the end of the preview interval. Typically, the viewer will be informed of the length of the preview time by the source or promoter of the pay per view TV programs. The removal of power from the remote terminal may defeat the termination of the preview period, the generation or downloading of a signal indicating that the viewer should be charged for the authorized TV program and/or the transmission of a report message from the remote terminal to the central station.
Viewers may also attempt to avoid payment for authorized programs by disconnecting the remote terminal from their non-dedicated telephone line. For example, it is contemplated that a remote terminal such as disclosed by the Martin et al. patent '486, which transmits report messages on a predetermined periodic basis, could be easily defeated by first ascertaining such periodic basis and disconnecting the viewer's telephone from the remote terminal at those times. In addition, a viewer intending to avoid payment for authorized programs, may attempt to intercept the report message to ascertain the format and content of the message, whereby such a report message could be altered to reflect no authorized pay per view TV programs.